On the compositional partitioning during phase transformation in a binary ferromagnetic MnAl alloy
On the compositional partitioning during phase transformation in a binary ferromagnetic MnAl alloy
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DOI：
10.1016/j.actamat.2019.05.037
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发表时间：
2019-08
期刊：
影响因子：
9.4
通讯作者：
D. Palanisamy;D. Raabe;B. Gault
中科院分区：
文献类型：
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作者：
D. Palanisamy;D. Raabe;B. Gault
我们介绍了通过原子级电子显微镜和原子探针断层扫描的相关使用实现的经典大规模固态相变模式的新视角。这在具有类 Heusler 特性的二元 MnAl 合金中得到了证明。在该系统中，由高温ε相大量转变形成的τ相是亚稳态和铁磁性的。这种转变导致新生长的 τ 相内出现高密度的微孪晶。跨界面边界和微孪晶原子结构的原子尺度成分分析揭示了τ相生长过程中结构修饰和成分分配的参与。转变期间迁移的 τ/ε 界面边界有助于实现这一点。最后，讨论了微孪晶对平衡相成核的作用以及缺陷和相形成对磁性能的影响。
We introduce a new perspective on the classical massive mode of solid-state phase transformation enabled by the correlative use of atomic-scale electron microscopy and atom probe tomography. This is demonstrated in a binary MnAl alloy which has Heusler-like characteristics. In this system, theτphase formed by a massive transformation from the high-temperature ε phase is metastable and ferromagnetic. The transformation results in a high density of micro-twins inside the newly grown τ phase. Atomic-scale compositional analysis across the interface boundaries and atomic structure of the micro-twins reveals the involvement of both structural modification and also the compositional partitioning during the growth of theτphase. This is assisted by the migratingτ/εinterface boundary during transformation. Finally, the role of micro-twins on nucleating the equilibrium phases and the influence of the defects and phase formation on the magnetic properties are discussed.